This is the third lesson in the unit on chemical reactions. Up to this point, students have learned how to tell if a chemical reaction has occurred, how to write word and skeleton equations, and how to balance chemical equations. In this lesson we will begin to explore the 5 major types of chemical reactions. Students will learn the general pattern for each type of reaction and also the characteristics of each type. This topic requires a lot of practice, so much of this lesson will be devoted to practicing classifying and predicting chemical reactions. By the end of this lesson, students will be able to describe each of the 5 major types of reactions, classify chemical reactions as one of the 5 major types, and also predict the products of chemical reactions.
Objectives
Students will be able to:
identify the 5 basic types of chemical reactions: synthesis, combustion, decomposition, single replacement, and double replacement.
classify chemical reactions into the five major categories (synthesis, combustion, decomposition, single replacement, and double replacement).
give an example of each type of chemical reaction.
describe the characteristics of each type of chemical reaction.
Single Replacement Reaction: Magnesium Ribbon, Hydrochloric Acid
Double Replacement Reaction:
Practicing Classifying Chemical Reactions Worksheet
Instruction
Opening (10 minutes)
When students walk into the classroom, two things will be written on the board: the Chemistry Checkpoint question and the objectives for the days lesson.
Chemistry Checkpoint: Balance the following chemical reactions: CuCl2 + H2S ---> CuS + HCl, C2H6 + O2 ---> CO2 + H2O
Once attendance is taken and students have completed their Chemistry Checkpoint question, we will go over the homework from the previous night. I will have a few students write their answers on the board and we will go over them as a class. This will serve as good review and practice, as well as informal assessment for me to see how students are doing with balancing chemical equations.
After we go over the homework I will make sure there are no questions, then I will pass out the Types of Chemical Reactions Notes/Handout.
Middle (60 minutes)
When introducing each type of chemical reaction,I will give a brief overview of the reaction, then I will do a demonstration that shows that type of reaction. I will also have students "perform" a skit that demonstrates each reaction type.
Synthesis Reaction
A + B --> AB
In a synthesis reaction, a new substance is created from two or more reactants
The hallmark of this reaction is that there is only ONE product
"Skit: Love at First Sight": Boy + Girl --> Couple (I will have one boy and one girl walk towards each other from opposite directions, then join and hold hands)
Demonstration: 2Mg (s) + O2 (g) --> 2MgO (s). Holding the magnesium ribbon with tongs, I will burn the ribbon in the Bunsen Burner flame. The magnesium will turn white and I will ask students if a reaction has occurred and how they know.
I will write the equation on the board and ask them to make a connection to the skit that their classmates performed.
Decomposition Reaction
AB --> A + B
In a decomposition reaction, a single reactant falls apart into two or more products.
The hallmark of this reaction is that there is only ONE reactant
"Skit: The Break Up": A couple breaks up (Boy and girl standing in the front of the room "fight and break up" and walk to opposite sides of the room.
Demonstration: Elephant Toothpaste! 2H2O2 -->2O +O2. KI is added to hydrogen peroxide as a catalyst. The hydrogen peroxide has a few drops of detergent in it. The production of O2 (g) causes the detergent to foam! I will ask students if a reaction has occurred and how they can tell.
I will write the equation on the board and ask them to make a connection to the skit that their classmates performed.
Single Replacement Reaction
AB + C --> AC + B -or- D + EF --> ED + F
In a single replacement reaction, one element replaces another element in a compound
In order for a single replacement reaction to occur, A must be more reactive than B in order to combine with C
The hallmark of these reactions is that there is always a SINGLE PERSON AND A COUPLE on both sides of the reaction
"Skit: Soap-Opera Reaction": Boy-Girl couple is approached by another girl. The boy leaves his girlfriend behind and goes with the new girl.
Demonstration: Mg (s) + HCl --> MgCl + H2
I will write the equation on the board and ask them to make a connection to the skit that their classmates performed.
Double Replacement Reaction
AB + CD --> AD + CB
In a double replacement reaction, two pairs of elements switch partners - like square dancing
The hallmark of this reaction is that there are always TWO COUPLES on BOTH SIDES of the reaction
"Skit: Square Dancing": Match up two sets of partners and have them square dance (switch partners). Ask: who was paired up to begin with? Who is paired up now?
Demonstration: Pb(NO3)2 (aq)+ 2NaI (aq) --> 2NaNO3 (aq) + PbI2 (s). When the lead (II) nitrate solution is added to the sodium iodide solution, the solution will turn yellow. I will as students if a reaction is occurring and how they can tell
I will write the equation on the board and ask them to make a connection to the skit that their classmates performed.
Combustion Reaction
Closing (15 minutes)
After completing the demonstrations and skits for all the reaction types, I will hand out the Types of Chemical Reactions Practice Worksheet. Time permitting, I will ask students to start working on it in class, if there is not time, it will be a homework assignment.
I will take a few minutes towards the end of class to check in with students on their Adopt-A-Chemical Reaction projects. I will ask if they are having any trouble, or if they have found anything interesting about their reaction that relates to today's lesson, or that they would like to share with the class. I will remind them that their balanced equation, type of reaction, and word equation are due next class.
Title: Classifying Chemical Reactions
Summary
This is the third lesson in the unit on chemical reactions. Up to this point, students have learned how to tell if a chemical reaction has occurred, how to write word and skeleton equations, and how to balance chemical equations. In this lesson we will begin to explore the 5 major types of chemical reactions. Students will learn the general pattern for each type of reaction and also the characteristics of each type. This topic requires a lot of practice, so much of this lesson will be devoted to practicing classifying and predicting chemical reactions. By the end of this lesson, students will be able to describe each of the 5 major types of reactions, classify chemical reactions as one of the 5 major types, and also predict the products of chemical reactions.Objectives
Students will be able to:Materials
Instruction
Opening (10 minutes)
Middle (60 minutes)
Closing (15 minutes)
Notes